Portion of a watch



FIG. 1 is a perspective view of a portion of a watch showing our new design;

FIG. 2 is another perspective view thereof; and,

FIG. 3 is a front view thereof.

The broken line showing of various regions of the watch is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a portion of a watch, as shown and described. 